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Topic: Most efficient sleep (Read 984 times) previous topic - next topic

ximinez

I'm designing a circuit to run from battery, using a nano without a led (and bypassing the voltage regulator). I want to sleep (PWR DOWN) for 15 or 20 minutes.

I can wake up every 8s with the watchdog, stay awake for ~65ms eating ~45mA (spending in total more than 7 seconds awake during a 15 minute period), or I can try to find a component that can generate an interrupt every 15 minutes - using less power than what the arduino uses awake during the same period.

A simple RTC (PCF8563, powered from the same source as the arduino) would use only 0.25uA, but seems like an awfully complex component for a relatively simple task.

Are there any other low-power components I can use to generate an interrupt after a given amount of minutes? (Needs to be able to work between 1.9v and 3.2v)

raschemmel

Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

ximinez

"LM555 astable multivibrator"
I tried playing around with a 555 calculator to see if I could get 15 minutes, but I couldn't get more than 476 seconds or thereabouts.

jremington

Quote
I can wake up every 8s with the watchdog, stay awake for ~65ms eating ~45mA (spending in total more than 7 seconds awake during a 15 minute period)
65 ms is just the longest of several wake-up options.
You can do a lot to reduce the "~45mA" power consumption while awake.
http://www.gammon.com.au/power

raschemmel

Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

treadon

ATtiny85
The ATtiny85 can also be put into sleep mode for 8s intervals.  If you turn off the ADC it uses almost no power, and can be put back to sleep immediately.

raschemmel

#6
Apr 25, 2016, 06:06 pm Last Edit: Apr 25, 2016, 06:10 pm by raschemmel
NO NO NO !

OP asked for cheap IC to make 15 minute interrupt generator:

ATtiny85 using millis()
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

treadon

The ATtiny85 using millis() will use 10mA of power, I'm not sure he wants that.

raschemmel

Quote
I can wake up every 8s with the watchdog, stay awake for ~65ms eating ~45mA (spending in total more than 7 seconds awake during a 15 minute period), or I can try to find a component that can generate an interrupt every 15 minutes - using less power than what the arduino uses awake during the same period
The arduino nano uses  about 45 mA so technically it meets the OP's criteria, unless he decides to change his mind.
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

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